Market demand for smaller and more powerful electronic devices has driven the development of compact packages having increased functionality. One particularly economical and useful semiconductor package includes a supporting leadframe, a chip electrically coupled to the leadframe, and encapsulating material molded over a first surface of the leadframe and the chip. The encapsulating material thus defines an upper exterior surface of the package, while a second non-encapsulated surface of the leadframe defines a lower exterior surface of the package that is configured to be coupled to a printed circuit board. Conventionally, these forms of semiconductor packages provide multiple input and output connection areas, and are attachable to a wide range of semiconductor boards.
The leadframe provides a support structure for the package. Some semiconductor packages include chip-by-chip packages that have a first chip coupled to but electrically isolated from a metal leadframe, and a second chip coupled to and in electrical communication with the leadframe. It is desired to maintain a potential voltage difference between the first chip and the second chip in these chip-by-chip packages. However, over time, metal ions from the metal leadframe will diffuse through the isolating adhesion layer coupling the first electrically isolated chip to the leadframe. Eventually, the undesirable diffusion of the metal ions to a backside of the first electrically isolated chip will negatively affect performance of the chip and performance of the semiconductor package.
For these and other reasons there is a need for the present invention.